The stars were out Sunday in Indian Wells, California, for the BNP Paribas Open, as both of the top seeds in the men's and women's singles draws were in action.

Roger Federer continued his second-round match with Federico Delbonis after rain interrupted their contest Saturday, while Simona Halep got her tournament started against Caroline Dolehide.

Twelve-time Grand Slam winner Novak Djokovic also made his first appearance since losing to Hyeon Chung in the fourth round of the Australian Open.

Alexander Zverev was another surprise departure at Indian Wells after he fell to Portugal's Joao Sousa in three sets.

Below are the scores from Sunday and a brief recap for the respective draws. The full BNP Paribas Open schedule is available on the tournament'sofficial site.

Men's Singles Results

Sunday, March 11

No. 1 Roger Federer def. Federico Delbonis: 6-3, 7-6(6)

No. 2 Marin Cilic def. Marton Fucsovics: 7-5, 6-3

No. 6 Juan Martin del Potro def. Alex De Minaur: 6-2, 6-1

No. 8 Jack Sock def. Thomas Fabbiano: 6-2, 7-5

Yuki Bhambri def. No. 9 Lucas Pouille: 6-4, 6-4

Taro Daniel def. No. 10 Novak Djokovic: 7-6(3), 4-6, 6-1

Marcos Baghdatis def. No. 14 Diego Schwartzman: 7-5, 6-4

Gael Monfils def. No. 15 John Isner: 6-7(5), 7-6(3), 7-5

No. 18 Sam Querrey def. Mischa Zverev: 6-4, 7-5

Dudi Sela def. No. 21 Kyle Edmund: 6-4, 6-4

Pierre-Hugues Herbert def. No. 24 Gilles Muller: 6-3, 7-5

No. 28 Feliciano Lopez def. Ernesto Escobedo: 6-4, 6-3

No. 29 David Ferrer def. Tennys Sandgren: 6-2, 7-6(3)

No. 31 Philipp Kohlschreiber def. Tim Smyczek: 1-6, 6-4, 6-4

No. 32 Milos Raonic def. Felix Auger-Aliassime: 6-4, 6-4

Leonardo Mayer def. Ruben Bemelmans: 6-4, 6-1

Joao Sousa def. No. 4 Alexander Zverev: 7-5, 5-7, 6-4

By far the biggest surprise of the day came from Djokovic's three-set loss to unseeded Taro Daniel. Some rust was to be expected from Djokovic after his elbow issues forced him to take an extended break, but few expected a second-round exit at Indian Wells.

"For me it felt like first match I ever played on the tour," Djokovic said after the match, per the ATP World Tour's official site. "Very weird. I mean, I just completely lost rhythm, everything. Just struggled also a little bit with the health the last couple of weeks."

Sunday basically represented the worst-case scenario for Djokovic. Not only did he lose, but his performance created serious questions about his health and whether he can position himself as a threat for the 2018 French Open.

Djokovic wasn't alone in falling to an unseeded qualifier. Ninth-seeded Lucas Pouille and 14th-seeded Diego Schwartzman lost in straight sets.

New York Times writer Ben Rothenberg also remarked upon Sousa's shock 7-5, 5-7, 6-4 victory over No. 4 seed Zverev, who would have been expected to contend for the title again considering his history in the contest:

Gael Monfils also upset John Isner, giving the 15th-seeded American his earliest departure at Indian Wells since 2013.

Both Federer and No. 2 seed Marin Cilic avoided the upset bug. They encountered some trouble, with Federer going to a tiebreak in the second set and Cilic winning his first set 7-5 over Marton Fucsovics. Federer particularly labored, committing 40 unforced errors.

Because his match with Delbonis was delayed, Federer will be back on the court Monday, so the 36-year-old could be in danger when he faces Filip Krajinovic.

Women's Singles Results

Sunday, March 11

No. 1 Simona Halep def. Caroline Dolehide: 1-6, 7-6(3), 6-2

No. 5 Karolina Pliskova def. No. 32 Shuai Zhang: 7-5, 5-7, 6-3

Petra Martic def. No. 6 Jelena Ostapenko: 6-3, 6-3

Amanda Anisimova def. No. 9 Petra Kvitova: 6-2, 6-4

No. 13 Sloane Stephens def. Victoria Azarenka: 6-1, 7-5

Qiang Wang def. No. 14 Kristina Mladenovic: 6-1, 6-2

Maria Sakkari def. No. 17 CoCo Vandeweghe, 6-2, 6-4

Marketa Vondrousova def. Aryna Sabalenka: 6-2, 6-2

No. 10 Angelique Kerber def. Ekaterina Makarova: 3-6, 6-4, 6-2

Naomi Osaka def. Sachia Vickery: 6-3, 6-3

Halep had her hands full with Dolehide. The 19-year-old cruised in the first set, with the WTA showing off one of her winners from the third game:

Dolehide had an opportunity to put the match away in the second set after she and Halep played to a tiebreak. The Australian Open runner-up seemed to shift gears in the tiebreaker, only surrendering three points to Dolehide, and that was the turning point in the match.

Dolehide ran out of gas in the third, as she was unable to seriously challenge Halep in the final set.

"In the end, I think I was stronger on the legs," Halep said, per David Kane of the WTA's official site. "Also, when I had to finish the point, I did."

Kerber booked her place in the third round after the No. 10 seed dropped the opening set in her clash against Ekaterina Makarova to eventually win 3-6, 6-4, 6-2, and Naomi Osaka defeated American Sachia Vickery 6-3, 6-3.

Petra Kvitova wasn't so fortunate. The two-time Wimbledon champion lost in straight sets to 16-year-old American Amanda Anisimova, who's the No. 149-ranked player in the world. The New York Times' Christopher Clarey added more perspective on the enormity of the result:

Anisimova's unlikely run at the BNP Paribas Open may not extend much further, though. She'll meet the fifth-seeded Karolina Pliskova in the fourth round. Even if Anisimova loses, she has already made a big impression in Indian Wells.